Brain stimulation can involve evoking a neural response by touching or otherwise activating the brain, either directly or indirectly. For example, brain stimulation can be used to evoke neuromodulation, which can be used in treating various neurological disorders, as well as other conditions involving the brain, such as psychiatric disorders. Brain stimulation can thus be used to treat neuropathic pain, Parkinson's disease, depression, obsessive-compulsive disorder, essential tremor, and brain tumors, among other disorders. Additionally, systems and techniques for brain stimulation can be used to analyze various conditions, including epilepsy, Alzheimer's disease, multiple sclerosis, hydrocephalus, stroke, trigeminal neuralgia, and traumatic brain injury. Furthermore, neuromodulation can be used in brain mapping techniques.
Deep brain stimulation (DBS) is a brain stimulation technique using electrodes implanted in the brain to transmit electrical impulses to specific parts of the brain. However, DBS can have adverse neuropsychiatric side-effects due at least in part to its invasive nature. Another brain stimulation technique is optogenetics, which involves using light to stimulate genetically modified neurons. However, such gene modification can be challenging and undesirable.
Non-invasive brain stimulation techniques can include transcranial magnetic stimulation (TMS), which can be used to stimulate small regions of the brain using a magnetic field. However, TMS can have poor spatial resolution, and can have inadequate depth penetration. Furthermore, the effects of TMS can be relatively short lasting (e.g., in the millisecond range).
Thus, there remains an opportunity for improved techniques for non-invasive brain stimulation.